Aircraft with sustaining rotors



' v 'AIRCRAFT WITH SUSTAININGVOTORS v I VFiled Agg. 2s. 1940 /NVEN 70APatented Sert 2L; 1,1942

'PATlaaNTjffoFFlclzl wrrnsus'ramnvcao'ronls r James AllanJamieson-Bennett, Esker, England.

'f assignor to Autoziro Company o! America,v

. Willow Grove, Pa., a corporation o! Delaware Application August z3,1940, serial No. 353,801' In Great Britamnecember 1, 193s 12 claims.(ci. 24e-1s)` v 'Thisinvention relates'torotaplanes, -i.'e. aircraftsustainedin normal ightwholly or prin-v cipally byy the axial thrust ofan autorotative rotor (orrotors) andv is especially concerned withdevices forobtain-ing a so-called jump-start or direct takeoi, inwhich"the rotor ispower driven beforetaking-oil toa considerably higherspeed than that utilisedv in night, for which purpose'the blade angle-ismarkedly decreased, prei-V `erably to the'no-lift value,.and th e storedenergy utilised to produce a direct lift by increasing-the bladeangle'to-the normal value or greater con.

currentlyl with cessation-of thelpower drive, e. g. by disengagementof'a clutch;

It'has'-been,proposedtot causethe blade anale 4to vary automatically asrequiredforthis; pur-.y pose by articulating each'blade to the hub by.the

withj its. axis--l acutely inclined 'to i the biadeaxis on' theIea'di'ngside ofthe latter and a drag., or

alph'af"`(a) 4pivot with'its-axisfmaking an acute'" angle-with'therotational axis when projected' on leverages. l

` matic variationsoffblade angleistobtained by the combinationeftwodeltapivots (Inand'a) 'one atleastof which-has its y axis f acutelyinclined to l.. the'bladeLaxisg-andapplyin'gfthe drive .totheintermediate*nnenib-er''ofiA the .compound 61, fr

joint by means;A of ian .independent` driving member oatingwithreference to the huband coaxial v therewith, togetherfwith appropriate'c :onneclj`.ions,

which may' includev a system 'of' leverages or system of gears. T he"axis of the falpha or drag.'

pivots maybe in a. 'plane perpendicular tothe blade axis andrmaki'ne 'anAacute angle withthe rotational specied in my United States Patentl Nor.2,121,536 'for "^any. other; form" of -One formof'theinvention isillustratedbvY thef; accompanyingdiagrammatic drawing, of which Fig. 1is a part sectional plan view of/the 'head' of athree-bladed rotorvshowing part of lone blade and its connection'tothehe'ad;

ing of the rotor prior to' take-off; and

. 'Fig'. 3` is-a further side elevation showing the:l

positions occupied bytheparts during flight;

Inthe drawing.:` l' l y 'I'he upper part of the pylon or other rotorsllPDOrting structureI indicated generallv'at II,`

, has a. ilange I2, above which there extends a mast portion Il whichsupports the rotor head proper,

indicated at Il, and a floating drive member I5. The` rotor head I4 andthe' floating drive member vI5are both mounted for rotation upon thema'st I3, upon bearings which are' not illustrated-as I theylformno-part Aof the invention as such; said mountings may be ofany`appr`opriate type. The

rotor head Il has three apertured radiallugs I6 t with which the threeblades respectively arev con-V i nectedabout horizontal axes.` shown in.the' `-151carsefof -onebladel l Ijl, the connection with the rotor ,headIlc'omprlses a lead-lag or a pivotV I8 and 'two -ila'pping vor '65pivots I9 and 2li respec- 1. '-tively, these latter being'inclined toone another,

The linkindicat'ed 2nat 12|; joiningthe 'two pivo'ts I9 and 20 ,isfaston the pin 22'of the pivot 2li which .pin,22 has nas'shownclearly inFig. 1.

alsovfast thereon a 4gearwheel', `theteeth of which mesh `with those ofa vcrown-wheel 24 car,-

vried. by' aiidrotatable' 'as 'one with thegnoating 25drive-"meniber[I5.v Angular movement of the' link y 2| aboutthe pivot 20is limited by a stop,25,

Fi'gsrzand-Sfon the'lug, liwithwhich the link` 2Ieoope`1'ates at theendsof a notch 26 formed t I orthe purposettherein. For driving vthe rotor,a drive-shaft. 21,journal1ed'near its upper end?? `in the ange`fI1-2fofthejsupporting structure II, t

hasV f asttliereonfa'pinion 28 which meshes withThedirection-otjfro'tation is a'sindica'ted-bv4 the arrow.. inFig."1,"tl ie drive being Aimparted to the rotor,as--will'beapparent, viathe gearing A23,

u and the 1mi:V 2 1. The gearing z3, u is 'such'that'rotationfofthedrive member I5 will move the link- 2l in aclockwise'v direction as far as 40 permitted Iby.` thestopf 25 tov the-position shown in Fig.: 2, and, as'aresult, owing to the mutual finclination of the .e pivots I9 and 20, the pitch angle of the bladeswill bev decreased to a va1ue determinedby the inclinations of thev two6 pivots landliy the position o'f the stop 25.. In practice.thisdecreased ,blaciepitch'angle will be substanf I' When, the rotorspeed havin-g"reached an appropriately. high value, the- 'drive theretois termi- 504v movement of.- tli`e -link 2| in an upward Fig. 2 isacorresponding side elevation showing the positions occupied by-theparts lduxin`gtdriv direction takes place automaticallyundertheitisnecessl'y In the arrangement shown the outer a pivot'Ilisinclinedandtheinnerpivotllisatright angles to the longitudinal axisoi the blade l1.'

Theincllnedpivot Ilisalsoindicatedbymin order that its position maybeclearly distin- Amashed.

be determined by a stop, the inclinations of the` two pivots beingchosen appropriately.

It is' to be noted that with an arrangement according to the invention,the blades may assume temporarily upon cessation of drive to the rotorpitch angles greater thanduring normal autorotative iimctioning oi therotor during night. During driving oi the rotor prior to takeoii, thereis substantially zero lift and the coning angle of the blades is zero.ceases, the' blades `assume positions giving the above mentioned greaterpitch angles and upon the subsequent coning up of the blades normalpitch angles obtain. The coning up of the blades reduces the pitch angleii A/A0 is negative; where A0=blade angle increment and AO=con When thedrive'y axis acutely inclined to the blade axis, with rotor ing angleincrement, that is, if the inner a pivot is inclined outwardly on theleading side of the also disclosed in my copending application SerialNo. 353,808, filed August 23, 1940, wherein said multiple blade pivotarrangements per se, and in association with means acting on theintermediate pivot link to change the blade pitch, are claimed.

What I claim is:

l. In a rotaplane as set forth, and for obtaining variation of bladepitch angle for direct takeoii, the combination oi' blade connections tothe rotor hub including two napping pivots, one at least of which hasits axis acutely inclined to the blade axis with means including anindependent-floating drive member for applying rotor driving torque tointermediate members uniting the two iiapping pivots of each blade,respec- "tively, whereby the transmission oi driving torque to the rotoreects movement about said iiapping pivots with consequent change ofblade pitch angle.

2. In a rotaplane as set forth, and for obtaining variation of bladepitch angle for direct takeoiI, the combination of blade connections tothe rotor hub including two napping pivots which are inclined to oneanother with means including an independent floating drive member forapplying rotor driving, torque to intermediate members uniting the twonapping pivots of each blade, respectively, whereby the transmission ofdriving torque to the rotor effects movement about said flapping pivotswith consequent change of blade pitch angle.

3. In a-rotaplane as set forth, mechanism for automatically varying theblade pitch angle condriving Ameans applying the driving effort to anintermediate member uniting said pivots through the medium of anindependent iloating drive member disposed coaxially' of the hub.

4. In a rotaplane as set forth, mechanism for automatically varying theblade pitch angle concurrently with disconnection of the rotor drive fordirect take-dii, and comprising the combination of 'a blade mountingsystem in which each blade is articulated to the hub by means oi twoflapping pivots, one at least of which has its axis acutely inclined tothe blade axis, with rotor driving means applying the driving effort toan intermediate member uniting said pivots through the medium of anindependent oating drive member disposed coaxially oi the hub, saidcombination including gear connections between a rotor drive shaft andthe independent iioating drive member.

5. In a rotaplane as set forth, mechanism for automatically varying theblade pitch angle concurrently with disconnection of the rotor drive fordirect take-cti, and comprising the combination of a blade mountingsystem in which each blade is articulated to the hub by means of twonapping pivots, onel at least oi which has its axis acutely inclined tothe blade axis, with rotor driving means applying the driving eii'ort toan intermediate member uniting said pivots through the medium of anindependent iioating drive member disposed coaxially oi the hub, saidcombination including connections including levers between a rotor driveshaft and the independent oating drive member.

6. In a rotaplane as set forth, mechanism for automatically varying theblade pitch angle concurrently with disconnection of the r'otor drivefor direct take-od, and comprising the combination of a blade mountingsystem inf whichA each blade is articulated to the hub by means oi twoflapping pivots, one at least of which has its axis acutely inclined tothe'blade axis, with rotor -driving means applying the driving eiort toan intermediate member uniting said pivots through the medium of anindependent iioating drive member disposed coaxially of the hub, saidcombination including stops limiting the extent to which eachintermediate member can move about the corresponding inner nappingpivot.

'7. In a rotaplane as set forth, mechanism for automatically varying theblade pitch angle concurrently with disconnection vof the rotor drivefor direct take-oi,v and comprising the combination of a blade mountingsystem in which each blade is articulated to the hub by means of twoflapping pivots, one atleast of which has its axis acutely inclined tothe blade axis, with rotor driving means applying the driving eiort toan intermediate member uniting said pivots through the medium of anindependent floating drive member disposed coaxially of the hub, saidcombination including stops limiting the extent to which eachintermediate member can move about the corresponding inner flappingpivot, whereby the position of said intermediate members, re-

currently with disconnection of the rotor drive for direct take-ofi, andcomprising the combinaspectively, corresponding to substantially zeroblade pitch angle is determined.

8. Ina rotaplane as set forth, mechanism for automatically varying theblade' pitch angle concurrently with disconnection of the rotor drivefor direct take-ofi', and comprising the combination of a blade mountingsystem in which each sedan flapping pivots, one at least oi which hasits axis acutely inclined to the blade axis, with rotor drivling meansapplying the driving eirort to an intermediate member uniting sindpivots through the medium of an independent floating drive memberdisposed coaxially of the hub, said combination including stops limitingthe extent to which each intermediate member can move about thecorrespondingl inner napping pivot, whereby the position of saidintermediate members, respectively, corresponding to maximum blade pitchangle appropriate to the high initial rotor speed is determined.

9. For an aircraft having a pivoted blade sustaining rotor. for eachblade, a pair o! pivots with their axes positionedto provide for bladevswinging movement in the same'general direc-V tion, the axes of saidtwopivots being somewhat inclined with respect to each other'and the axisof at least one of said pivots being inclined with reit erence to aplane perpendicular to the blade axis to provide for conjoint swingingand pitch change movement of the blade about said Vone pivot axis, andmechanism for driving the rotor including drive means coupled with ablade pivot member and providing for pivotal blade movement in a senseto alter the blade pitch.

10. For ad aircraft having a pivoted blade sustaining rotor, a hub, foreach blade a pair of blade mounting pivots one or which is radiallyoiset from the other, the pivots being arranged to eect pitch changemovement of the blade upon compound movement thereof about the axes ofsaid pivots, and rotor drive mechanism opera tive uponl transmission oftorque to the rotor blades to eirect compound blade movement about saidpivot axes.

11. A construction in accordance with claim l0 in which the majorcomponent of movement of the blade about each of said pivots is in theiiapping sense.

12. For an aircraft having a pivoted blade sustaining rotor and adisconnectible drive, for each blade, a pair of pivots with theiraxespositioned to provide tor blade movement generally in the nappingsense, the axis o! at least one of said pivots being so positioned as tointroduce a com-v ponent of pitch change movement of the blade, andmeans for transmitting the driving torque to the rotor blades ina'manner establishing dierf ent blade pitch positions as between thecondition of -power drive and free rotation.

JAIWES ALLAN JAMESON BENNETT.

